The term “nipple confusion” can strike fear into the hearts of new moms bent on breast-feeding. To avoid it, mothers are advised to wait several weeks before introducing pacifiers — or bottles — to infants; that way, babies will become champs at suckling at the breast before getting introduced to the different sucking patterns associated with pacifiers or bottles.

But a new study — from researchers intent on promoting exclusive breast-feeding, no less — is questioning whether that’s sound advice.

Intent upon boosting breast-feeding rates, nurses atOregon Health & Science University (OHSU) stopped routinely giving binkies to breastfed newborns starting in Dec. 2010. Pacifiers were still available, but they were sequestered in a locked cabinet, where they were earmarked for special circumstances — a baby undergoing a painful procedure such as circumcision or an infant born addicted to drugs who was suffering withdrawal symptoms.

OHSU already had a relatively high rate of exclusive breast-feeding of nearly 80%, but researchers at the hospital were hoping to push it to 90%. Restricting pacifiers would help reach that goal, they believed. After all, not giving pacifiers to breast-fed babies is one of the 10 steps required if hospitals are to be considered “Baby-Friendly,” a coveted designation that fewer than 10% of U.S. hospitals have achieved.

Yet OHSU, which is trying to achieve Baby-Friendly certification, found that limiting pacifier use resulted in decreased rates of exclusive breast-feeding. After tracking 2,249 babies born between June 2010 and August 2011, they noted that exclusive breast-feeding dropped from 79% of infants between July and November 2010 to 68% between January to August 2011.

At the same time, the percentage of breast-fed babies receiving supplemental formula increased from 18% to 28%. Meanwhile, the proportion of babies who received only formula didn’t fluctuate.

“We were really surprised and disappointed because we had hoped that limiting pacifiers would improve breast-feeding rates,” says Dr. Carrie Phillipi, an associate professor of pediatrics at OHSU and co-author of the study, which was presented Monday at the annual meeting of the Pediatric Academic Societies in Boston.

Phillipi pointed out that the observational study has plenty of limitations — it wasn’t randomized and there were no controls, to name a few — but the results were too intriguing to keep quiet. “There is tons of energy around improving exclusive breast-feeding rates,” says Phillipi. “We felt it was worthwhile publicizing to ask what really is the evidence for routinely restricting pacifiers.”

Complicating matters further is a recommendation from the American Academy of Pediatrics — which advises exclusive breast-feeding for the first six months of life — to introduce pacifiers at about four weeks, once breast-feeding is well-established, in order to help slash the risk of SIDS. “It’s a really complicated message we’re delivering to parents who want to do the best for their children.”

Very few high-quality studies of the relationship between breast-feeding and pacifier use exist, says Phillipi, and those that do don’t clearly establish that pacifiers negatively impact breast-feeding rates.

So does the concept of nipple confusion not exist? While it makes sense because the sucking mechanism used with breast, bottle and pacifiers is thought to be different, the reality appears to suggest otherwise. “We know what’s best for moms and babies and that’s to breast-feed,” says Phillipi. “We can’t state parents should or shouldn’t use pacifiers, but this does make you wonder. Especially early in life, we want babies on the breast a lot. But we are seeing that the issue may be more complex.”